DESCRIPTION

Egg - The white, glistening egg is oval to spherical in
shape and 0.33 mm long.

Larva - This short-legged wireworm has a pale yellow to
reddish-brown body and a brown, flattened head. When mature, it
ranges from 21 to 25 mm in length.

Pupa - The white, soft-bodied pupa has no protective
covering and is approximately the same size and shape as the
adult.

BIOLOGY

Distribution - Melanotus communis wireworms can be
found throughout the United States, but are most abundant in the
midwestern and southeastern states. They tend to be common in newly
planted sod or no-till planted corn.

Host Plants - The wireworm, M. communis, feeds on the
roots of many grasses including corn and many small grain crops.
It may also attack the roots, seeds, and tubers of many flower and
vegetable crops, especially potatoes. This species has been known
to infest tobacco.

Damage - The most significant wireworm damage occurs to
germinating seeds and seedling plants. Wireworms feed on the seed
and often leave only the empty hull (pericarp). Roots are snipped
off as they emerge and often rot. Corn seedlings 5 to 20 cm high
are damaged when wireworms tunnel in or feed superficially upon the
underground stem and taproot area of plants. Recent injury of this
kind may be characterized by the presence of rot and jelly-like
plant secretions. Above-ground symptoms include yellowing and
wilting or death of terminal shoots. Melanotus communis does
more damage during cold, wet springs, especially in fields which
have been grassy or weedy for the previous year or more.

Life History - This wireworm species has a six-year life
cycle. In June of the first year, adults deposit eggs singly among
the roots of grasses. First instar larvae emerge in July and begin
feeding on roots. The first year, larvae continue to develop
throughout the summer and overwinter in the ground as second
instars. Most of these immatures remain in the larval stage for 5
years although life cycles as short as 3 years have been reported.
In late July or August of the sixth year, mature larvae construct
oval cells 15 to 30 cm deep in the soil and pupate. Melanotus
communis beetles emerge about 18 days later and feed on pollen
before hibernating in protected areas. They become active and
deposit eggs the following May or June.

CONTROL

Cultural methods of controlling wireworms include summer plowing of
fallow fields and crop rotation. Plowing to a depth of 23 cm (9
inches) around the first of August will dry out the soil and break
up the insects' cell-like chambers, killing large numbers of pupae
and adults. Legumes are more tolerant to feeding by these pests and
are therefore excellent crops with which to rotate corn. Rotating
corn with small grains and planting crops in well-drained soils are
additional control measures effective against Melanotus
communis.